#include <stdio.h>
#include <time.h>

int main(void)
{
        enum Color {red = 10,  green, blue};
        enum Color rgb;

        for (rgb = red; rgb <= blue; rgb++)
        {
                printf("rgb is %d\n", rgb);
        }


        return 0;
}

/*
 * red = 100;
 * gcc test3.c && ./a.out
 * test3.c: In function ‘main’:
 * test3.c:9:6: error: lvalue required as left operand of assignment
 *   red = 100;
 *
 *   */
